Semiconductor Device and Method of Forming Discontinuous ESD Protection Layers Between Semiconductor Die

ABSTRACT

A semiconductor wafer has a plurality of semiconductor die separated by a saw street. The wafer is mounted to dicing tape. The wafer is singulated through the saw street to expose side surfaces of the semiconductor die. An ESD protection layer is formed over the semiconductor die and around the exposed side surfaces of the semiconductor die. The ESD protection layer can be a metal layer, encapsulant film, conductive polymer, conductive ink, or insulating layer covered by a metal layer. The ESD protection layer is singulated between the semiconductor die. The semiconductor die covered by the ESD protection layer are mounted to a temporary carrier. An encapsulant is deposited over the ESD protection layer covering the semiconductor die. The carrier is removed. An interconnect structure is formed over the semiconductor die and encapsulant. The ESD protection layer is electrically connected to the interconnect structure to provide an ESD path.

FIELD OF THE INVENTION

The present invention relates in general to semiconductor devices and,more particularly, to a semiconductor device and method of formingdiscontinuous ESD protection layers between semiconductor die.

BACKGROUND OF THE INVENTION

Semiconductor devices are commonly found in modern electronic products.Semiconductor devices vary in the number and density of electricalcomponents. Discrete semiconductor devices generally contain one type ofelectrical component, e.g., light emitting diode (LED), small signaltransistor, resistor, capacitor, inductor, and power metal oxidesemiconductor field effect transistor (MOSFET). Integrated semiconductordevices typically contain hundreds to millions of electrical components.Examples of integrated semiconductor devices include microcontrollers,microprocessors, charged-coupled devices (CCDs), solar cells, anddigital micro-mirror devices (DMDs).

Semiconductor devices perform a wide range of functions such ashigh-speed calculations, transmitting and receiving electromagneticsignals, controlling electronic devices, transforming sunlight toelectricity, and creating visual projections for television displays.Semiconductor devices are found in the fields of entertainment,communications, power conversion, networks, computers, and consumerproducts. Semiconductor devices are also found in military applications,aviation, automotive, industrial controllers, and office equipment.

Semiconductor devices exploit the electrical properties of semiconductormaterials. The atomic structure of semiconductor material allows itselectrical conductivity to be manipulated by the application of anelectric field or base current or through the process of doping. Dopingintroduces impurities into the semiconductor material to manipulate andcontrol the conductivity of the semiconductor device.

A semiconductor device contains active and passive electricalstructures. Active structures, including bipolar and field effecttransistors, control the flow of electrical current. By varying levelsof doping and application of an electric field or base current, thetransistor either promotes or restricts the flow of electrical current.Passive structures, including resistors, capacitors, and inductors,create a relationship between voltage and current necessary to perform avariety of electrical functions. The passive and active structures areelectrically connected to form circuits, which enable the semiconductordevice to perform high-speed calculations and other useful functions.

Semiconductor devices are generally manufactured using two complexmanufacturing processes, i.e., front-end manufacturing, and back-endmanufacturing, each involving potentially hundreds of steps. Front-endmanufacturing involves the formation of a plurality of die on thesurface of a semiconductor wafer. Each die is typically identical andcontains circuits formed by electrically connecting active and passivecomponents. Back-end manufacturing involves singulating individual diefrom the finished wafer and packaging the die to provide structuralsupport and environmental isolation.

One goal of semiconductor manufacturing is to produce smallersemiconductor devices. Smaller devices typically consume less power,have higher performance, and can be produced more efficiently. Inaddition, smaller semiconductor devices have a smaller footprint, whichis desirable for smaller end products. A smaller die size may beachieved by improvements in the front-end process resulting in die withsmaller, higher density active and passive components. Back-endprocesses may result in semiconductor device packages with a smallerfootprint by improvements in electrical interconnection and packagingmaterials.

Many semiconductor devices are susceptible to damage from electrostaticdischarge (ESD). FIG. 1 a shows a conventional arrangement with aplurality of semiconductor die 10 having active surface 12 and contactpads 14 mounted to double-sided adhesive layer 16 applied over temporarycarrier 18. ESD protection layer 20 is formed over semiconductor die 10.ESD protection layer 20 is a physically and electrically continuouslayer formed over semiconductor die 10, as well as area 22 between thesemiconductor die. An encapsulant 24 is formed over the semiconductordie 10 and carrier 18. In FIG. 1 b, adhesive layer 16 and temporarycarrier 18 are removed and a build-up interconnect structure 26 isformed over active surface 12 and encapsulant 24 of semiconductor die10. ESD protection layer 20 remains as a physically and electricallycontinuous layer over semiconductor die 10, as well as area 22 betweenthe semiconductor die, during formation of build-up interconnectstructure 26.

Electrostatic charges can accumulate when the double-sided adhesivelayer 16 and temporary carrier 18 are removed. The electrostatic chargesmust be removed to avoid shortening the life cycle of semiconductor die10. An ionizer is commonly used to neutralize the electrostatic charges.However, ionizers add cost to the manufacturing process. ESD protectionlayer 20 also removes electrostatic charges but requires expensive andtime consuming deposition processes, such as chemical vapor deposition(CVD) and sputtering, to form the physically and electrically continuouslayer.

SUMMARY OF THE INVENTION

A need exists for cost effective ESD protection scheme for semiconductordie. Accordingly, in one embodiment, the present invention is a methodof making a semiconductor device comprising the steps of providing asemiconductor wafer having a plurality of semiconductor die separated bya saw street, mounting the semiconductor wafer to dicing tape,singulating the semiconductor wafer through the saw street to exposeside surfaces of the semiconductor die, forming an ESD protection layerover the semiconductor die and around the exposed side surfaces of thesemiconductor die, singulating the ESD protection layer to make the ESDprotection layer discontinuous between the semiconductor die, mountingthe semiconductor die covered by the ESD protection layer to a temporarycarrier, depositing an encapsulant over the ESD protection layercovering the semiconductor die, removing the temporary carrier, andforming an interconnect structure over the semiconductor die andencapsulant. The ESD protection layer is electrically connected to theinterconnect structure to provide an ESD path.

In another embodiment, the present invention is a method of making asemiconductor device comprising the steps of providing a semiconductorwafer having a plurality of first semiconductor die separated by a sawstreet, singulating the semiconductor wafer through the saw street toexpose side surfaces of the first semiconductor die, forming an ESDprotection layer over the first semiconductor die and around the exposedside surfaces of the first semiconductor die, singulating the ESDprotection layer between the first semiconductor die, mounting the firstsemiconductor die covered by the ESD protection layer to a carrier,depositing an encapsulant over the ESD protection layer, removing thecarrier, and forming an interconnect structure over the firstsemiconductor die and encapsulant.

In another embodiment, the present invention is a method of making asemiconductor device comprising the steps of providing a semiconductorwafer having a plurality of first semiconductor die separated by a sawstreet, singulating the semiconductor wafer through the saw street toexpose side surfaces of the first semiconductor die, forming an ESDprotection layer over the first semiconductor die and around the exposedside surfaces of the first semiconductor die, singulating the ESDprotection layer between the first semiconductor die, and depositing anencapsulant over the ESD protection layer.

In another embodiment, the present invention is a semiconductor devicecomprising a plurality of semiconductor die and ESD protection layerformed over the semiconductor die and around side surfaces of thesemiconductor die. The ESD protection layer is discontinuous between thesemiconductor die. An encapsulant is deposited over the ESD protectionlayer. An interconnect structure is formed over the semiconductor dieand encapsulant. The ESD protection layer is electrically connected tothe interconnect structure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 a-1 b illustrate a conventional semiconductor die with acontinuous ESD protection layer;

FIG. 2 illustrates a PCB with different types of packages mounted to itssurface;

FIGS. 3 a-3 c illustrate further detail of the representativesemiconductor packages mounted to the PCB;

FIGS. 4 a-4 l illustrate a process of forming discontinuous ESDprotection layers over side surfaces and back surface of a semiconductordie;

FIG. 5 illustrates the semiconductor die with the discontinuous ESDprotection layer formed over its side surfaces and back surface;

FIGS. 6 a-6 j illustrate a process of forming the discontinuous ESDprotection layer as encapsulant film;

FIG. 7 illustrates the semiconductor die with the discontinuous ESDprotection layer formed as encapsulant film over its side surfaces andback surface;

FIGS. 8 a-8 i illustrate a process of forming the discontinuous ESDprotection layers as an insulating layer and conductive layer;

FIG. 9 illustrates the semiconductor die with the discontinuous ESDprotection layer formed as an insulating layer and conductive layer overits side surfaces and back surface;

FIG. 10 illustrates side-by-side semiconductor die each covered by thediscontinuous ESD protection layer;

FIG. 11 illustrates side-by-side semiconductor die, one die covered bythe discontinuous ESD protection layer and one die without the ESDprotection layer;

FIG. 12 illustrates stacked semiconductor die, one die covered by thediscontinuous ESD protection layer and one die without the ESDprotection layer; and

FIG. 13 illustrates stacked semiconductor die, each die covered by thediscontinuous ESD protection layer.

DETAILED DESCRIPTION OF THE DRAWINGS

The present invention is described in one or more embodiments in thefollowing description with reference to the figures, in which likenumerals represent the same or similar elements. While the invention isdescribed in terms of the best mode for achieving the invention'sobjectives, it will be appreciated by those skilled in the art that itis intended to cover alternatives, modifications, and equivalents as maybe included within the spirit and scope of the invention as defined bythe appended claims and their equivalents as supported by the followingdisclosure and drawings.

Semiconductor devices are generally manufactured using two complexmanufacturing processes: front-end manufacturing and back-endmanufacturing. Front-end manufacturing involves the formation of aplurality of die on the surface of a semiconductor wafer. Each die onthe wafer contains active and passive electrical components, which areelectrically connected to form functional electrical circuits. Activeelectrical components, such as transistors and diodes, have the abilityto control the flow of electrical current. Passive electricalcomponents, such as capacitors, inductors, resistors, and transformers,create a relationship between voltage and current necessary to performelectrical circuit functions.

Passive and active components are formed over the surface of thesemiconductor wafer by a series of process steps including doping,deposition, photolithography, etching, and planarization. Dopingintroduces impurities into the semiconductor material by techniques suchas ion implantation or thermal diffusion. The doping process modifiesthe electrical conductivity of semiconductor material in active devices,transforming the semiconductor material into an insulator, conductor, ordynamically changing the semiconductor material conductivity in responseto an electric field or base current. Transistors contain regions ofvarying types and degrees of doping arranged as necessary to enable thetransistor to promote or restrict the flow of electrical current uponthe application of the electric field or base current.

Active and passive components are formed by layers of materials withdifferent electrical properties. The layers can be formed by a varietyof deposition techniques determined in part by the type of materialbeing deposited. For example, thin film deposition may involve chemicalvapor deposition (CVD), physical vapor deposition (PVD), electrolyticplating, and electroless plating processes. Each layer is generallypatterned to form portions of active components, passive components, orelectrical connections between components.

The layers can be patterned using photolithography, which involves thedeposition of light sensitive material, e.g., photoresist, over thelayer to be patterned. A pattern is transferred from a photomask to thephotoresist using light. The portion of the photoresist patternsubjected to light is removed using a solvent, exposing portions of theunderlying layer to be patterned. The remainder of the photoresist isremoved, leaving behind a patterned layer. Alternatively, some types ofmaterials are patterned by directly depositing the material into theareas or voids formed by a previous deposition/etch process usingtechniques such as electroless and electrolytic plating.

Depositing a thin film of material over an existing pattern canexaggerate the underlying pattern and create a non-uniformly flatsurface. A uniformly flat surface is required to produce smaller andmore densely packed active and passive components. Planarization can beused to remove material from the surface of the wafer and produce auniformly flat surface. Planarization involves polishing the surface ofthe wafer with a polishing pad. An abrasive material and corrosivechemical are added to the surface of the wafer during polishing. Thecombined mechanical action of the abrasive and corrosive action of thechemical removes any irregular topography, resulting in a uniformly flatsurface.

Back-end manufacturing refers to cutting or singulating the finishedwafer into the individual die and then packaging the die for structuralsupport and environmental isolation. To singulate the die, the wafer isscored and broken along non-functional regions of the wafer called sawstreets or scribes. The wafer is singulated using a laser cutting toolor saw blade. After singulation, the individual die are mounted to apackage substrate that includes pins or contact pads for interconnectionwith other system components. Contact pads formed over the semiconductordie are then connected to contact pads within the package. Theelectrical connections can be made with solder bumps, stud bumps,conductive paste, or wirebonds. An encapsulant or other molding materialis deposited over the package to provide physical support and electricalisolation. The finished package is then inserted into an electricalsystem and the functionality of the semiconductor device is madeavailable to the other system components.

FIG. 2 illustrates electronic device 50 having a chip carrier substrateor printed circuit board (PCB) 52 with a plurality of semiconductorpackages mounted on its surface. Electronic device 50 may have one typeof semiconductor package, or multiple types of semiconductor packages,depending on the application. The different types of semiconductorpackages are shown in FIG. 2 for purposes of illustration.

Electronic device 50 may be a stand-alone system that uses thesemiconductor packages to perform one or more electrical functions.Alternatively, electronic device 50 may be a subcomponent of a largersystem. For example, electronic device 50 may be a graphics card,network interface card, or other signal processing card that can beinserted into a computer. The semiconductor package can includemicroprocessors, memories, application specific integrated circuits(ASIC), logic circuits, analog circuits, RF circuits, discrete devices,or other semiconductor die or electrical components.

In FIG. 2, PCB 52 provides a general substrate for structural supportand electrical interconnect of the semiconductor packages mounted on thePCB. Conductive signal traces 54 are formed over a surface or withinlayers of PCB 52 using evaporation, electrolytic plating, electrolessplating, screen printing, or other suitable metal deposition process.Signal traces 54 provide for electrical communication between each ofthe semiconductor packages, mounted components, and other externalsystem components. Traces 54 also provide power and ground connectionsto each of the semiconductor packages.

In some embodiments, a semiconductor device has two packaging levels.First level packaging is a technique for mechanically and electricallyattaching the semiconductor die to an intermediate carrier. Second levelpackaging involves mechanically and electrically attaching theintermediate carrier to the PCB. In other embodiments, a semiconductordevice may only have the first level packaging where the die ismechanically and electrically mounted directly to the PCB.

For the purpose of illustration, several types of first level packaging,including wire bond package 56 and flip chip 58, are shown on PCB 52.Additionally, several types of second level packaging, including ballgrid array (BGA) 60, bump chip carrier (BCC) 62, dual in-line package(DIP) 64, land grid array (LGA) 66, multi-chip module (MCM) 68, quadflat non-leaded package (QFN) 70, and quad flat package 72, are shownmounted on PCB 52. Depending upon the system requirements, anycombination of semiconductor packages, configured with any combinationof first and second level packaging styles, as well as other electroniccomponents, can be connected to PCB 52. In some embodiments, electronicdevice 50 includes a single attached semiconductor package, while otherembodiments call for multiple interconnected packages. By combining oneor more semiconductor packages over a single substrate, manufacturerscan incorporate pre-made components into electronic devices and systems.Because the semiconductor packages include sophisticated functionality,electronic devices can be manufactured using cheaper components and astreamlined manufacturing process. The resulting devices are less likelyto fail and less expensive to manufacture resulting in a lower cost forconsumers.

FIGS. 3 a-3 c show exemplary semiconductor packages. FIG. 3 aillustrates further detail of DIP 64 mounted on PCB 52. Semiconductordie 74 includes an active region containing analog or digital circuitsimplemented as active devices, passive devices, conductive layers, anddielectric layers formed within the die and are electricallyinterconnected according to the electrical design of the die. Forexample, the circuit may include one or more transistors, diodes,inductors, capacitors, resistors, and other circuit elements formedwithin the active region of semiconductor die 74. Contact pads 76 areone or more layers of conductive material, such as aluminum (Al), copper(Cu), tin (Sn), nickel (Ni), gold (Au), or silver (Ag), and areelectrically connected to the circuit elements formed withinsemiconductor die 74. During assembly of DIP 64, semiconductor die 74 ismounted to an intermediate carrier 78 using a gold-silicon eutecticlayer or adhesive material such as thermal epoxy or epoxy resin. Thepackage body includes an insulative packaging material such as polymeror ceramic. Conductor leads 80 and wire bonds 82 provide electricalinterconnect between semiconductor die 74 and PCB 52. Encapsulant 84 isdeposited over the package for environmental protection by preventingmoisture and particles from entering the package and contaminating die74 or wire bonds 82.

FIG. 3 b illustrates further detail of BCC 62 mounted on PCB 52.Semiconductor die 88 is mounted over carrier 90 using an underfill orepoxy-resin adhesive material 92. Wire bonds 94 provide first levelpackaging interconnect between contact pads 96 and 98. Molding compoundor encapsulant 100 is deposited over semiconductor die 88 and wire bonds94 to provide physical support and electrical isolation for the device.Contact pads 102 are formed over a surface of PCB 52 using a suitablemetal deposition process such as electrolytic plating or electrolessplating to prevent oxidation. Contact pads 102 are electricallyconnected to one or more conductive signal traces 54 in PCB 52. Bumps104 are formed between contact pads 98 of BCC 62 and contact pads 102 ofPCB 52.

In FIG. 3 c, semiconductor die 58 is mounted face down to intermediatecarrier 106 with a flip chip style first level packaging. Active region108 of semiconductor die 58 contains analog or digital circuitsimplemented as active devices, passive devices, conductive layers, anddielectric layers formed according to the electrical design of the die.For example, the circuit may include one or more transistors, diodes,inductors, capacitors, resistors, and other circuit elements withinactive region 108. Semiconductor die 58 is electrically and mechanicallyconnected to carrier 106 through bumps 110.

BGA 60 is electrically and mechanically connected to PCB 52 with a BGAstyle second level packaging using bumps 112. Semiconductor die 58 iselectrically connected to conductive signal traces 54 in PCB 52 throughbumps 110, signal lines 114, and bumps 112. A molding compound orencapsulant 116 is deposited over semiconductor die 58 and carrier 106to provide physical support and electrical isolation for the device. Theflip chip semiconductor device provides a short electrical conductionpath from the active devices on semiconductor die 58 to conductiontracks on PCB 52 in order to reduce signal propagation distance, lowercapacitance, and improve overall circuit performance. In anotherembodiment, the semiconductor die 58 can be mechanically andelectrically connected directly to PCB 52 using flip chip style firstlevel packaging without intermediate carrier 106.

FIGS. 4 a-4 l illustrate, in relation to FIGS. 2 and 3 a-3 c, a processof forming discontinuous ESD protection layers over side surfaces andback surface of a semiconductor die. FIG. 4 a shows a semiconductorwafer 120 with a base substrate material 122, such as silicon,germanium, gallium arsenide, indium phosphide, or silicon carbide, forstructural support. A plurality of semiconductor die or components 124is formed on wafer 120 separated by saw streets 126, as described above.

FIG. 4 b shows a cross-sectional view of a portion of semiconductorwafer 120. Each semiconductor die 124 has an active surface 130containing analog or digital circuits implemented as active devices,passive devices, conductive layers, and dielectric layers formed withinthe die and electrically interconnected according to the electricaldesign and function of the die. For example, the circuit may include oneor more transistors, diodes, and other circuit elements formed withinactive surface 130 to implement analog circuits or digital circuits,such as digital signal processor (DSP), ASIC, memory, or other signalprocessing circuit. Semiconductor die 124 may also contain IPDs, such asinductors, capacitors, and resistors, for RF signal processing.

An electrically conductive layer 132 is formed over active surface 130using PVD, CVD, electrolytic plating, electroless plating process, orother suitable metal deposition process. Conductive layer 132 can be oneor more layers of Al, Cu, Sn, Ni, Au, Ag, or other suitable electricallyconductive material. Conductive layer 132 operates as contact padselectrically connected to the circuits on active surface 130.

Semiconductor wafer 120 is mounted to dicing tape 136, as shown in FIG.4 c. In FIG. 4 d, semiconductor wafer 120 is singulated through sawstreet 126 down to dicing tape 136 using saw blade or laser cutting tool138 to expose side surfaces 142 of semiconductor die 124.

In FIG. 4 e, a conductive layer 140 is formed over the exposed sidesurfaces 142 of semiconductor die 124, i.e., in the singulated sawstreet 126. Conductive layer 140 is also formed over back surface 144,opposite active surface 130. In one embodiment, conductive layer 140 canbe one or more layers Al, Cu, Sn, Ni, Au, Ag, or other suitableelectrically conductive material. Conductive layer 140 is formed usingelectrolytic plating, electroless plating process, or other suitablemetal deposition process. In metal form, conductive layer 140 has athickness of 0.1 to 2.0 micrometers (μm) over back surface 144.Alternatively, conductive layer 140 can be an electrically conductivepolymer or electrically conductive ink, i.e., polymer or ink basematerial with electrically conductive particles, having a thickness lessthan 100 μm, preferably 20-50 μm. For example, the conductive polymercan be polyacetylene, polyphenylenevinylene, polypyrrole, polythiophene,polyaniline, polyphenylene, or other organic polymer. The conductivepolymer or conductive ink is formed by printing, sputtering, or vapordeposition over a metal mesh or other intermediate conductive layerformed over semiconductor die 124. Depending on the material, conductivelayer 140 can also be formed by stencil printing, screen printing, spincoating, or needle dispensing. Conductive layer 140 operates as an ESDprotection layer for semiconductor die 124.

In FIG. 4 f, ESD protection layer 140 is singulated betweensemiconductor die 124 down to dicing tape 136 using saw blade or lasercutting tool 148. Saw blade or laser cutting tool 148 is typicallynarrower than saw blade or laser cutting tool 138 so that ESD protectionlayer 140 remains covering side surfaces 142. After singulation, ESDprotection layer 140 is discontinuous between semiconductor die 124while still covering side surfaces 142 and back surface 144 ofsemiconductor die 124.

In FIG. 4 g, a temporary substrate or carrier 150 contains sacrificialbase material such as silicon, polymer, polymer composite, metal,ceramic, glass, glass epoxy, beryllium oxide, or other suitablelow-cost, rigid material for structural support. An interface layer ortape 152 is applied over carrier 150 as a double-sided adhesive layerreleasable by heat or ultraviolet (UV) light.

Semiconductor 124 a covered by ESD protection layer 140 is removed fromdicing tape 136 and mounted to interface layer 152 over carrier 150using pick and place operation. Likewise, semiconductor 124 b covered byESD protection layer 140 is removed from dicing tape 136 and mounted tointerface layer 152, as shown in FIG. 4 h. ESD protection layer 140formed over semiconductor die 124 a is discontinuous, i.e., physicallyseparated and electrically isolated, from ESD protection layer 140formed over semiconductor die 124 b. Semiconductor die 124 a and 124 b,each with a separate and discontinuous ESD protection layer 140, mountedto carrier 150 is referred to as a “reconfigured wafer.”

In FIG. 4 i, an encapsulant or molding compound 154 is deposited oversemiconductor die 124 a and 124 b and carrier 150 in an amount thatcovers ESD protection layer 140 formed over side surfaces 142 and backsurface 144 of semiconductor die 124 a and 124 b. Encapsulant 154 isdeposited using a paste printing, compressive molding, transfer molding,liquid encapsulant molding, vacuum lamination, spin coating, or othersuitable applicator. Encapsulant 154 can be polymer composite material,such as epoxy resin with filler, epoxy acrylate with filler, or polymerwith proper filler. Encapsulant 154 is non-conductive andenvironmentally protects the semiconductor device from external elementsand contaminants.

In FIG. 4 j, temporary carrier 150 and interface layer 152 are removedby chemical etching, mechanical peel-off, CMP, mechanical grinding,thermal bake, UV light, laser scanning, or wet stripping.

In FIG. 4 k, a bottom-side build-up interconnect structure 158 is formedover active surface 130 of semiconductor die 124 a and 124 b andencapsulant 154. The build-up interconnect structure 158 includes anelectrically conductive layer 160 formed using a patterning and metaldeposition process such as sputtering, electrolytic plating, andelectroless plating. Conductive layer 160 can be one or more layers ofAl, Cu, Sn, Ni, Au, Ag, or other suitable electrically conductivematerial. One portion of conductive layer 160 is electrically connectedto contact pads 132 of semiconductor die 124 a and 124 b. Anotherportion of conductive layer 160 is electrically connected to ESDprotection layer 140 as a low impedance ground point. Other portions ofconductive layer 160 can be electrically common or electrically isolateddepending on the design and function of the semiconductor device.

The build-up interconnect structure 158 further includes an insulatingor passivation layer 162 formed between conductive layers 160 andcontaining one or more layers of silicon dioxide (SiO2), silicon nitride(Si3N4), silicon oxynitride (SiON), tantalum pentoxide (Ta2O5), aluminumoxide (Al2O3), or other material having similar insulating andstructural properties. The insulating layer 162 is formed using PVD,CVD, printing, spin coating, spray coating, sintering or thermaloxidation.

In FIG. 4 l, an electrically conductive bump material is deposited overbuild-up interconnect structure 158 and electrically connected toconductive layer 160 using an evaporation, electrolytic plating,electroless plating, ball drop, or screen printing process. The bumpmaterial can be Al, Sn, Ni, Au, Ag, Pb, Bi, Cu, solder, and combinationsthereof, with an optional flux solution. For example, the bump materialcan be eutectic Sn/Pb, high-lead solder, or lead-free solder. The bumpmaterial is bonded to conductive layer 160 using a suitable attachmentor bonding process. In one embodiment, the bump material is reflowed byheating the material above its melting point to form spherical balls orbumps 164. In some applications, bumps 164 are reflowed a second time toimprove electrical contact to conductive layer 160. The bumps can alsobe compression bonded to conductive layer 160. Bumps 164 represent onetype of interconnect structure that can be formed over conductive layer160. The interconnect structure can also use bond wires, stud bump,micro bump, or other electrical interconnect.

Semiconductor die 124 a and 124 b are singulated with saw blade or lasercutting tool 166 into individual semiconductor devices.

FIG. 5 shows semiconductor device 168 after singulation. Semiconductordie 124 is electrically connected to build-up interconnect structure 158and bumps 164. The active and passive circuits formed within activesurface 130 of semiconductor die 124 are susceptible to damage from ESDevents. Electrostatic charges can accumulate, for example during removalof carrier 150 and interface layer 152. The electrostatic charges mustbe removed to avoid shortening the life cycle of semiconductor die 124.Conductive layer 140 provides ESD protection for semiconductor die 124by neutralizing the electrostatic charges. Conductive layer 140 providesan ESD discharge path 170 through conductive layer 160 and bumps 164 toan external low-impedance ground point to safely discharge theelectrostatic charges and protect semiconductor die 124. Theelectrostatic charges migrate toward ESD discharge path 170, which islower resistance than a path leading to contact pads 132 and activesurface 130. By depositing discontinuous ESD protection layer 140 overside surfaces 142 and back surface 144 of each semiconductor die 124, acost effective deposition process, such as stencil printing, screenprinting, spin coating, and needle dispensing, can be used.

In another embodiment, continuing from FIG. 4 d, a conductiveencapsulant film 174 is applied to tape carrier 176 and positioned oversemiconductor die 124, as shown in FIG. 6 a. Encapsulant film 174 can beb-staged curable flowable film encapsulant containing fillers such asalumina, copper, carbon black, gold, or platina. For example, theb-staged film can be epoxy resin containing electrically conductiveparticles and having a thickness less than 100 μm, preferably 20-50 μm.The conductive encapsulant film 174 operates as an ESD protection layerfor semiconductor die 124.

In FIG. 6 b, ESD protection layer 174 is laminated over semiconductordie 124. In FIG. 6 c, ESD protection layer 174 is cured and tape carrier176 is removed. In FIG. 6 d, ESD protection layer 174 is singulatedbetween semiconductor die 124 down to dicing tape 136 using saw blade orlaser cutting tool 178. After singulation, ESD protection layer 174 isdiscontinuous between semiconductor die 124 while still covering sidesurfaces 142 and back surface 144 of semiconductor die 124.

In FIG. 6 e, a temporary substrate or carrier 180 contains sacrificialbase material such as silicon, polymer, polymer composite, metal,ceramic, glass, glass epoxy, beryllium oxide, or other suitablelow-cost, rigid material for structural support. An interface layer ortape 182 is applied over carrier 180 as a double-sided adhesive layerreleasable by heat or UV light.

Semiconductor 124 a covered by ESD protection layer 174 is removed fromdicing tape 136 and mounted to interface layer 182 over carrier 180using pick and place operation. Likewise, semiconductor 124 b covered byESD protection layer 174 is removed from dicing tape 136 and mounted tointerface layer 182, as shown in FIG. 6 f. The ESD protection layer 174formed over semiconductor die 124 a is discontinuous, i.e., physicallyseparated and electrically isolated, from the ESD protection layer 174formed over semiconductor die 124 b. Semiconductor die 124 a and 124 b,each with discontinuous ESD protection layer 174, mounted to carrier 150is referred to as a “reconfigured wafer.”

In FIG. 6 g, an encapsulant or molding compound 184 is deposited oversemiconductor die 124 a and 124 b and carrier 180 in an amount thatcovers ESD protection layer 174 formed over side surfaces 142 and backsurface 144 of semiconductor die 124 a and 124 b. Encapsulant 184 isdeposited using a paste printing, compressive molding, transfer molding,liquid encapsulant molding, vacuum lamination, spin coating, or othersuitable applicator. Encapsulant 184 can be polymer composite material,such as epoxy resin with filler, epoxy acrylate with filler, or polymerwith proper filler. Encapsulant 184 is non-conductive andenvironmentally protects the semiconductor device from external elementsand contaminants.

In FIG. 6 h, temporary carrier 180 and interface layer 182 are removedby chemical etching, mechanical peel-off, CMP, mechanical grinding,thermal bake, UV light, laser scanning, or wet stripping.

In FIG. 6 i, a bottom-side build-up interconnect structure 188 is formedover active surface 130 of semiconductor die 124 a and 124 b andencapsulant 184. The build-up interconnect structure 188 includes anelectrically conductive layer 190 formed using a patterning and metaldeposition process such as sputtering, electrolytic plating, andelectroless plating. Conductive layer 190 can be one or more layers ofAl, Cu, Sn, Ni, Au, Ag, or other suitable electrically conductivematerial. One portion of conductive layer 190 is electrically connectedto contact pads 132 of semiconductor die 124 a and 124 b. Anotherportion of conductive layer 190 is electrically connected to ESDprotection layer 174 as a low impedance ground point. Other portions ofconductive layer 190 can be electrically common or electrically isolateddepending on the design and function of the semiconductor device.

The build-up interconnect structure 188 further includes an insulatingor passivation layer 192 formed between conductive layers 190 andcontaining one or more layers of SiO2, Si3N4, SiON, Ta2O5, Al2O3, orother material having similar insulating and structural properties. Theinsulating layer 192 is formed using PVD, CVD, printing, spin coating,spray coating, sintering or thermal oxidation.

In FIG. 6 j, an electrically conductive bump material is deposited overbuild-up interconnect structure 188 and electrically connected toconductive layer 190 using an evaporation, electrolytic plating,electroless plating, ball drop, or screen printing process. The bumpmaterial can be Al, Sn, Ni, Au, Ag, Pb, Bi, Cu, solder, and combinationsthereof, with an optional flux solution. For example, the bump materialcan be eutectic Sn/Pb, high-lead solder, or lead-free solder. The bumpmaterial is bonded to conductive layer 190 using a suitable attachmentor bonding process. In one embodiment, the bump material is reflowed byheating the material above its melting point to form spherical balls orbumps 194. In some applications, bumps 194 are reflowed a second time toimprove electrical contact to conductive layer 190. The bumps can alsobe compression bonded to conductive layer 190. Bumps 194 represent onetype of interconnect structure that can be formed over conductive layer190. The interconnect structure can also use bond wires, stud bump,micro bump, or other electrical interconnect.

Semiconductor die 124 a and 124 b are singulated with saw blade or lasercutting tool 196 into individual semiconductor devices.

FIG. 7 shows semiconductor device 198 after singulation. Semiconductordie 124 is electrically connected to build-up interconnect structure 188and bumps 194. The active and passive circuits formed within activesurface 130 of semiconductor die 124 are susceptible to damage from ESDevents. Electrostatic charges can accumulate, for example during removalof carrier 180 and interface layer 182. The electrostatic charges mustbe removed to avoid shortening the life cycle of semiconductor die 124.Encapsulant film 174 provides ESD protection for semiconductor die 124by neutralizing the electrostatic charges. Encapsulant film 174 providesan ESD discharge path 200 through conductive layer 190 and bumps 194 toan external low-impedance ground point to safely discharge theelectrostatic charges and protect semiconductor die 124. Theelectrostatic charges migrate toward ESD discharge path 200, which islower resistance than a path leading to contact pads 132 and activesurface 130. By depositing discontinuous ESD protection layer 174 overside surfaces 142 and back surface 144 of each semiconductor die 124, acost effective deposition process, such as stencil printing, screenprinting, spin coating, and needle dispensing, can be used.

In another embodiment, continuing from FIG. 4 d, an insulating ordielectric layer 210 is conformally formed over side surfaces 142 andback surface 144 of semiconductor die 124, as shown in FIG. 8 a. Theinsulating layer 210 contains one or more layers of SiO2, Si3N4, SiON,Ta2O5, Al2O3, or other material having similar insulating and structuralproperties. The insulating layer 210 is formed using PVD, CVD, printing,spin coating, spray coating, sintering or thermal oxidation

In FIG. 8 b, a conductive layer 212 is formed over insulating layer 210,i.e., over side surfaces 142 in the singulated saw street 126 and backsurface 144. In one embodiment, conductive layer 212 can be one or morelayers Al, Cu, Sn, Ni, Au, Ag, or other suitable electrically conductivematerial. Conductive layer 212 is formed using electrolytic plating,electroless plating process, or other suitable metal deposition process.In metal form, conductive layer 212 has a thickness of 0.1 to 2.0 μmover back surface 144. Alternatively, conductive layer 212 can be anelectrically conductive polymer or electrically conductive ink, i.e.,polymer or ink base material with electrically conductive particles,having a thickness less than 100 μm, preferably 20-50 μm. For example,the conductive polymer can be polyacetylene, polyphenylenevinylene,polypyrrole, polythiophene, polyaniline, polyphenylene, or other organicpolymer. The conductive polymer or conductive ink is formed by printing,sputtering, or vapor deposition over a metal mesh or other intermediateconductive layer formed over semiconductor die 124. Depending on thematerial, conductive layer 212 can also be formed by stencil printing,screen printing, spin coating, or needle dispensing. The insulatinglayer 210 and conductive layer 212 operate as an ESD protection layerfor semiconductor die 124.

In FIG. 8 c, ESD protection layer 210-212 is singulated betweensemiconductor die 124 down to dicing tape 136 using saw blade or lasercutting tool 214. Saw blade or laser cutting tool 214 is typicallynarrower than saw blade or laser cutting tool 138 so that ESD protectionlayer 210-212 remains covering side surfaces 142. After singulation, ESDprotection layer 210-212 is discontinuous between semiconductor die 124while still covering side surfaces 142 and back surface 144 ofsemiconductor die 124.

In FIG. 8 d, a temporary substrate or carrier 220 contains sacrificialbase material such as silicon, polymer, polymer composite, metal,ceramic, glass, glass epoxy, beryllium oxide, or other suitablelow-cost, rigid material for structural support. An interface layer ortape 222 is applied over carrier 220 as a double-sided adhesive layerreleasable by heat or UV light.

Semiconductor 124 a with ESD protection layer 210-212 is removed fromdicing tape 136 and mounted to interface layer 222 over carrier 220using pick and place operation. Likewise, semiconductor 124 b with ESDprotection layer 210-212 is removed from dicing tape 136 and mounted tointerface layer 222, as shown in FIG. 8 e. ESD protection layer 210-212formed over semiconductor die 124 a is discontinuous, i.e., physicallyseparated and electrically isolated, from ESD protection layer 210-212formed over semiconductor die 124 b. Semiconductor die 124 a and 124 b,each with discontinuous ESD protection layer 210-212, mounted to carrier220 is referred to as a “reconfigured wafer.”

In FIG. 8 f, an encapsulant or molding compound 226 is deposited oversemiconductor die 124 a and 124 b and carrier 220 in an amount thatcovers ESD protection layer 210-212 formed over side surfaces 142 andback surface 144 of semiconductor die 124 a and 124 b. Encapsulant 226is deposited using a paste printing, compressive molding, transfermolding, liquid encapsulant molding, vacuum lamination, spin coating, orother suitable applicator. Encapsulant 226 can be polymer compositematerial, such as epoxy resin with filler, epoxy acrylate with filler,or polymer with proper filler. Encapsulant 226 is non-conductive andenvironmentally protects the semiconductor device from external elementsand contaminants.

In FIG. 8 g, temporary carrier 220 and interface layer 222 are removedby chemical etching, mechanical peel-off, CMP, mechanical grinding,thermal bake, UV light, laser scanning, or wet stripping.

In FIG. 8 h, a bottom-side build-up interconnect structure 228 is formedover active surface 130 of semiconductor die 124 a and 124 b andencapsulant 226. The build-up interconnect structure 228 includes anelectrically conductive layer 230 formed using a patterning and metaldeposition process such as PVD, CVD, sputtering, electrolytic plating,and electroless plating. Conductive layer 230 can be one or more layersof Al, Cu, Sn, Ni, Au, Ag, or other suitable electrically conductivematerial. One portion of conductive layer 230 is electrically connectedto contact pads 132 of semiconductor die 124 a and 124 b. Anotherportion of conductive layer 230 is electrically connected to conductivelayer 212 as a low impedance ground point. Other portions of conductivelayer 230 can be electrically common or electrically isolated dependingon the design and function of the semiconductor device.

The build-up interconnect structure 228 further includes an insulatingor passivation layer 232 formed between conductive layers 230 andcontaining one or more layers of SiO2, Si3N4, SiON, Ta2O5, Al2O3, orother material having similar insulating and structural properties. Theinsulating layer 232 is formed using PVD, CVD, printing, spin coating,spray coating, sintering or thermal oxidation.

In FIG. 8 i, an electrically conductive bump material is deposited overbuild-up interconnect structure 228 and electrically connected toconductive layer 230 using an evaporation, electrolytic plating,electroless plating, ball drop, or screen printing process. The bumpmaterial can be Al, Sn, Ni, Au, Ag, Pb, Bi, Cu, solder, and combinationsthereof, with an optional flux solution. For example, the bump materialcan be eutectic Sn/Pb, high-lead solder, or lead-free solder. The bumpmaterial is bonded to conductive layer 230 using a suitable attachmentor bonding process. In one embodiment, the bump material is reflowed byheating the material above its melting point to form spherical balls orbumps 234. In some applications, bumps 234 are reflowed a second time toimprove electrical contact to conductive layer 230. The bumps can alsobe compression bonded to conductive layer 230. Bumps 234 represent onetype of interconnect structure that can be formed over conductive layer230. The interconnect structure can also use bond wires, stud bump,micro bump, or other electrical interconnect.

Semiconductor die 124 a and 124 b are singulated with saw blade or lasercutting tool 236 into individual semiconductor devices.

FIG. 9 shows semiconductor device 238 after singulation. Semiconductordie 124 is electrically connected to build-up interconnect structure 228and bumps 234. The active and passive circuits formed within activesurface 130 of semiconductor die 124 are susceptible to damage from ESDevents. Electrostatic charges can accumulate, for example during removalof carrier 220 and interface layer 222. The electrostatic charges mustbe removed to avoid shortening the life cycle of semiconductor die 124.The insulating layer 210 and conductive layer 212 provides ESDprotection for semiconductor die 124 by neutralizing the electrostaticcharges. Conductive layer 212 provides an ESD discharge path 200 throughconductive layer 230 and bumps 234 to an external low-impedance groundpoint to safely discharge the electrostatic charges and protectsemiconductor die 124. The electrostatic charges migrate toward ESDdischarge path 240, which is lower resistance than a path leading tocontact pads 132 and active surface 130. By depositing discontinuous ESDprotection layer 210-212 over side surfaces 142 and back surface 144 ofeach semiconductor die 124, a cost effective deposition process, such asstencil printing, screen printing, spin coating, and needle dispensing,can be used. In addition, insulating layer 210 and conductive layer 212act as a shielding layer to suppress electromagnetic interference (EMI)and radio frequency interference (RFI). The insulating layer 210 alsoprevents electrical shorting between conductive layer 212 andsemiconductor die 124.

FIG. 10 shows two side-by-side semiconductor die 124 each with an ESDprotective layer 140 mounted to interconnect structure 158.

FIG. 11 shows two side-by-side semiconductor die 124, one die with ESDprotective layer 140 and one die without ESD protective layer 140,mounted to interconnect structure 158.

FIG. 12 shows an embodiment, continuing from FIG. 4 h, withsemiconductor die 124 covered by ESD protection layer 140 mounted to thetemporary carrier. A semiconductor die 250 has an active surface 252containing analog or digital circuits implemented as active devices,passive devices, conductive layers, and dielectric layers formed withinthe die and electrically interconnected according to the electricaldesign and function of the die. For example, the circuit may include oneor more transistors, diodes, and other circuit elements formed withinactive surface 252 to implement analog circuits or digital circuits,such as DSP, ASIC, memory, or other signal processing circuit.Semiconductor die 252 may also contain IPDs, such as inductors,capacitors, and resistors, for RF signal processing. A plurality ofcontact pads 254 is formed over active surface 252. A back surface 256of semiconductor die 250 is mounted to ESD protection layer 140 overback surface 144 of semiconductor die 124 with adhesive layer 258.

An encapsulant or molding compound 260 is deposited over semiconductordie 124 and 250 and the carrier using a paste printing, compressivemolding, transfer molding, liquid encapsulant molding, vacuumlamination, spin coating, or other suitable applicator. Encapsulant 260can be polymer composite material, such as epoxy resin with filler,epoxy acrylate with filler, or polymer with proper filler. Encapsulant260 is non-conductive and environmentally protects the semiconductordevice from external elements and contaminants.

A plurality of vias is formed through encapsulant 260 using laserdrilling, mechanical drilling, or deep reactive ion etching (DRIE). Thevias are filled with Al, Cu, Sn, Ni, Au, Ag, Ti, tungsten (W),poly-silicon, or other suitable electrically conductive material usingelectrolytic plating, electroless plating process, or other suitablemetal deposition process to form conductive vias 262.

The temporary carrier is removed by chemical etching, mechanicalpeel-off, CMP, mechanical grinding, thermal bake, UV light, laserscanning, or wet stripping.

A bottom-side build-up interconnect structure 264 is formed over activesurface 130 of semiconductor die 124 and encapsulant 260. The build-upinterconnect structure 264 includes an electrically conductive layer 266formed using a patterning and metal deposition process such as PVD, CVD,sputtering, electrolytic plating, and electroless plating. Conductivelayer 266 can be one or more layers of Al, Cu, Sn, Ni, Au, Ag, or othersuitable electrically conductive material. One portion of conductivelayer 266 is electrically connected to contact pads 132 of semiconductordie 124. Another portion of conductive layer 266 is electricallyconnected to ESD protection layer 140 as a low impedance ground point.Another portion of conductive layer 266 is electrically connected toconductive vias 262. Other portions of conductive layer 266 can beelectrically common or electrically isolated depending on the design andfunction of the semiconductor device.

The build-up interconnect structure 264 further includes an insulatingor passivation layer 268 formed between conductive layers 266 andcontaining one or more layers of SiO2, Si3N4, SiON, Ta2O5, Al2O3, orother material having similar insulating and structural properties. Theinsulating layer 268 is formed using PVD, CVD, printing, spin coating,spray coating, sintering or thermal oxidation. A plurality of bumps 270is formed over conductive layer 266.

A top-side build-up interconnect structure 272 is formed over activesurface 252 of semiconductor die 250 and encapsulant 260. The build-upinterconnect structure 272 includes an electrically conductive layer 274formed using a patterning and metal deposition process such as PVD, CVD,sputtering, electrolytic plating, and electroless plating. Conductivelayer 274 can be one or more layers of Al, Cu, Sn, Ni, Au, Ag, or othersuitable electrically conductive material. One portion of conductivelayer 274 is electrically connected to contact pads 254 of semiconductordie 250. Another portion of conductive layer 274 is electricallyconnected to conductive vias 262. Other portions of conductive layer 274can be electrically common or electrically isolated depending on thedesign and function of the semiconductor device.

The build-up interconnect structure 272 further includes an insulatingor passivation layer 276 formed between conductive layers 274 andcontaining one or more layers of SiO2, Si3N4, SiON, Ta2O5, Al2O3, orother material having similar insulating and structural properties. Theinsulating layer 276 is formed using PVD, CVD, printing, spin coating,spray coating, sintering or thermal oxidation.

FIG. 13 shows an embodiment, continuing from FIG. 5, with a plurality ofvias is formed through encapsulant 154 using laser drilling, mechanicaldrilling, or DRIE. The vias are filled with Al, Cu, Sn, Ni, Au, Ag, Ti,W, poly-silicon, or other suitable electrically conductive materialusing electrolytic plating, electroless plating process, or othersuitable metal deposition process to form conductive vias 280.

A top-side build-up interconnect structure 282 is formed overencapsulant 154. The build-up interconnect structure 282 includes anelectrically conductive layer 284 formed using a patterning and metaldeposition process such as PVD, CVD, sputtering, electrolytic plating,and electroless plating. Conductive layer 284 can be one or more layersof Al, Cu, Sn, Ni, Au, Ag, or other suitable electrically conductivematerial. One portion of conductive layer 284 is electrically connectedto conductive vias 280. Other portions of conductive layer 274 can beelectrically common or electrically isolated depending on the design andfunction of the semiconductor device.

The build-up interconnect structure 282 further includes an insulatingor passivation layer 286 formed between conductive layers 284 andcontaining one or more layers of SiO2, Si3N4, SiON, Ta2O5, Al2O3, orother material having similar insulating and structural properties. Theinsulating layer 286 is formed using PVD, CVD, printing, spin coating,spray coating, sintering or thermal oxidation.

Semiconductor device 288 includes semiconductor die 124 covered by ESDprotective layer 140 and electrically connected to build-up interconnectstructures 158 and 282 and bumps 164. Conductive layer 140 provides ESDprotection for semiconductor die 124. Two semiconductor devices 288 arestacked and electrically connected through interconnect structures 158and 282 and bumps 164.

While one or more embodiments of the present invention have beenillustrated in detail, the skilled artisan will appreciate thatmodifications and adaptations to those embodiments may be made withoutdeparting from the scope of the present invention as set forth in thefollowing claims.

1. A method of making a semiconductor device, comprising: providing asemiconductor wafer having a plurality of semiconductor die separated bya saw street; mounting the semiconductor wafer to dicing tape;singulating the semiconductor wafer through the saw street to exposeside surfaces of the semiconductor die; forming an electrostaticdischarge (ESD) protection layer over the semiconductor die and aroundthe exposed side surfaces of the semiconductor die; singulating the ESDprotection layer to make the ESD protection layer discontinuous betweenthe semiconductor die; mounting the semiconductor die covered by the ESDprotection layer to a temporary carrier; depositing an encapsulant overthe ESD protection layer covering the semiconductor die; removing thetemporary carrier; and forming an interconnect structure over thesemiconductor die and encapsulant, the ESD protection layer beingelectrically connected to the interconnect structure to provide an ESDpath.
 2. The method of claim 1, further including forming the ESDprotection layer over a back surface of the semiconductor die oppositean active surface of the semiconductor die.
 3. The method of claim 1,wherein forming the ESD protection layer includes forming a metal layerover the semiconductor die and around the exposed side surfaces of thesemiconductor die.
 4. The method of claim 1, wherein forming the ESDprotection layer includes: forming an insulating layer over thesemiconductor die and around the exposed side surfaces of thesemiconductor die; and forming a metal layer over the insulating layer.5. The method of claim 1, wherein forming the ESD protection layerincludes forming an encapsulant film, conductive polymer, or conductiveink over the semiconductor die and around the exposed side surfaces ofthe semiconductor die.
 6. The method of claim 1, further including:stacking a plurality of semiconductor die covered by the ESD protectivelayer; and electrically connecting the stacked semiconductor die.
 7. Amethod of making a semiconductor device, comprising: providing asemiconductor wafer having a plurality of first semiconductor dieseparated by a saw street; singulating the semiconductor wafer throughthe saw street to expose side surfaces of the first semiconductor die;forming an electrostatic discharge (ESD) protection layer over the firstsemiconductor die and around the exposed side surfaces of the firstsemiconductor die; singulating the ESD protection layer between thefirst semiconductor die; mounting the first semiconductor die covered bythe ESD protection layer to a carrier; depositing an encapsulant overthe ESD protection layer; removing the carrier; and forming aninterconnect structure over the first semiconductor die and encapsulant.8. The method of claim 7, wherein the ESD protection layer iselectrically connected to the interconnect structure.
 9. The method ofclaim 7, wherein forming the ESD protection layer includes forming ametal layer over the semiconductor die and around the exposed sidesurfaces of the semiconductor die.
 10. The method of claim 7, whereinforming the ESD protection layer includes: forming an insulating layerover the first semiconductor die and around the exposed side surfaces ofthe first semiconductor die; and forming a metal layer over theinsulating layer.
 11. The method of claim 7, wherein forming the ESDprotection layer includes forming an encapsulant film, conductivepolymer, or conductive ink over the semiconductor die and around theexposed side surfaces of the semiconductor die.
 12. The method of claim7, further including: stacking a plurality of first semiconductor diecovered by the ESD protective layer; and electrically connecting thestacked semiconductor die.
 13. The method of claim 7, further including:providing a second semiconductor die without the ESD protection layer;and mounting the second semiconductor die adjacent to or over the firstsemiconductor die covered by the ESD protection layer.
 14. A method ofmaking a semiconductor device, comprising: providing a semiconductorwafer having a plurality of first semiconductor die separated by a sawstreet; singulating the semiconductor wafer through the saw street toexpose side surfaces of the first semiconductor die; forming anelectrostatic discharge (ESD) protection layer over the firstsemiconductor die and around the exposed side surfaces of the firstsemiconductor die; singulating the ESD protection layer between thefirst semiconductor die; and depositing an encapsulant over the ESDprotection layer.
 15. The method of claim 14, further including formingan interconnect structure over the first semiconductor die andencapsulant.
 16. The method of claim 14, further including: mounting thefirst semiconductor die covered by the ESD protection layer to a carrierprior to depositing the encapsulant; depositing the encapsulant over theESD protection layer; and removing the carrier.
 17. The method of claim14, wherein forming the ESD protection layer includes forming a metallayer over the semiconductor die and around the exposed side surfaces ofthe semiconductor die.
 18. The method of claim 14, wherein forming theESD protection layer includes: forming an insulating layer over thefirst semiconductor die and around the exposed side surfaces of thefirst semiconductor die; and forming a metal layer over the insulatinglayer.
 19. The method of claim 14, wherein forming the ESD protectionlayer includes forming an encapsulant film, conductive polymer, orconductive ink over the semiconductor die and around the exposed sidesurfaces of the semiconductor die.
 20. The method of claim 14, furtherincluding: stacking a plurality of first semiconductor die covered bythe ESD protective layer; and electrically connecting the stackedsemiconductor die.
 21. A semiconductor device, comprising: a pluralityof semiconductor die; an electrostatic discharge (ESD) protection layerformed over the semiconductor die and around side surfaces of thesemiconductor die, the ESD protection layer being discontinuous betweenthe semiconductor die; an encapsulant deposited over the ESD protectionlayer; and an interconnect structure formed over the semiconductor dieand encapsulant, the ESD protection layer being electrically connectedto the interconnect structure.
 22. The semiconductor device of claim 21,wherein the ESD protection layer includes a metal layer.
 23. Thesemiconductor device of claim 21, wherein the ESD protection layerincludes: an insulating layer formed over the semiconductor die andaround the side surfaces of the semiconductor die; and a metal layerformed over the insulating layer.
 24. The semiconductor device of claim21, wherein the ESD protection layer includes an encapsulant film,conductive polymer, or conductive ink.
 25. The semiconductor device ofclaim 21, further including a plurality of semiconductor die covered bythe ESD protective layer and electrically connected through theinterconnect structure.